textproduct: Rapid City

KEY MESSAGES

- Unseasonably warm temperatures Thursday and Friday (10-20F above average).

- Elevated to near critical fire wx concerns across much of the area Friday afternoon and evening

- Much cooler this weekend with chances for light rain and possibly some snow Sunday.

DISCUSSION

(This Evening Through Wednesday) Issued at 1221 PM MDT Wed Oct 21 2026

Upper level ridge continues to influence conditions across the area today with light southerly flow and WAA supporting seasonably warm temperatures in the upper 50s to low 60s. Water vapor imagery shows subtle shortwave feature crossing the CWA with the only impacts being some mid to high level cloud cover moving over western SD. After a mild night, return flow and WAA ramps up over the region tomorrow with highs climbing into the upper 70s to low 80s across the western SD plains and northeastern WY. Rapid City itself could reach the low 80s, though high clouds in the afternoon could keep things slightly cooler. Regardless, it should be an unseasonably warm day across the area.

Northern stream shortwave moves through the Northern Plains late Friday. Southwest winds will pick up through the day Friday ahead of the attendant sfc cold front with gusts of 30-40 mph over much of the western SD plains and northeastern WY. Strong WAA through the day Friday will support highs well above average (70s to 80s across much of the western SD plains into northeastern WY). Rapid City could break a daily record with forecast highs of 83 (previous records were 82 and 80 in downtown Rapid City and at our airport respectively). The warm, dry, and windy conditions will support elevated to near critical fire wx concerns Friday afternoon. See Fire Wx Discussion for more details.

Current deterministic model guidance shows front will push through the region late Friday night through early Saturday morning with winds shifting to the northwest behind the front. Winds will remain gusty through the overnight hours into Saturday morning with most recent NAM runs showing modest pressure rises of 3-5 mb early Saturday morning. Strong CAA and 850-700mb winds of 30-40KT will support gusty northwest winds, especially over northwestern SD.

Upper level low over the desert SW will eject over the Central Plains by Sunday. As this low lifts northeastward and grazes the CWA, we could get a round of precip Sunday afternoon into Sunday evening. All deterministic runs and ensembles have been trending upwards in terms of QPF over the area Sunday. As for whether this QPF will be in the form of rain or snow, right now it's looking like mostly rain over the lower elevations of the plains with the higher elevations in the Black Hills being cold enough for snow. In terms of snow: The most recent GFS deterministic runs are the most aggressive with this system, showing several inches of accumulating snowfall over the Black Hills and portions of southwestern SD and the western SD plains. The Euro and Canadian models are a bit more conservative and show little, if any, snow accumulation. Given the recent warm temps and timing of snowfall (looking like this should be in the afternoon/evening hours). All of this to say: At this time it's not looking likely that we'd see much accumulation except for in the highest elevations of the Black Hills.

AVIATION

(For the 18Z TAFS Through 18Z Thursday) Issued At 1124 AM MDT Wed Oct 21 2026

VFR conditions are expected through the forecast period.

Main aviation changes will be centered around winds but overall concerns are low. Increased wind speeds, upwards of 10 to 20 kts, are likely through the tonight for NE WY and NW SD before a lull in speeds Thursday morning. Wind speeds increase again, up to 10 to 15 kts, for most of the area for Thursday afternoon.

FIRE WEATHER

Issued At 1221 PM MDT Wed Oct 21 2026

Increasing confidence in widespread elevated to near critical fire wx conditions over much of the area Friday afternoon as a cold front approaches the region. Southwest winds will increase across the region Friday morning into Friday afternoon ahead of the front with gusts of up to 40mph across northeastern WY. Temperatures will climb into the 70s to 80s across much of the western SD plains and northeastern WY, well above average for this time of year. Afternoon humidities will drop into the 20-30% range across northeastern WY, western SD plains, and foothills.

The unseasonably warm highs, low humidities, and gusty southwest winds will lead to elevated to near critical fire wx concerns across much of western SD into northeastern WY Friday afternoon. As of right now, am not considering any fire weather headlines for Friday afternoon due to humidities being above critical thresholds.

UNR WATCHES/WARNINGS/ADVISORIES

SD...None. WY...None.